Gamma probe with hand-piece control of detection parameters

ABSTRACT

Apparatus, techniques and systems are described for facilitating identification of a target area during a probe-guided radio-localization surgical procedure. The described apparatus, techniques and systems can be used to implement a nuclear-uptake mode controller integrated into a probe to allow a user to instantly switch between multiple nuclear-uptake modes directly from the probe hand-piece. For example, a nuclear-uptake mode controller integrated into the probe can be used to instantly switch between a high-sensitivity nuclear-up-take mode and a high-resolution nuclear-uptake mode to effectively identify the target area in the presence of interfering nuclear signals by better matching the probe&#39;s nuclear detection parameters to a search task for that target area.

PRIORITY CLAIM AND RELATED PATENT APPLICATION

This application claims priority of U.S. Provisional Application No.61/841,581 entitled “Gamma Probe with Hand-piece Control of DetectionParameters” and filed on Jul. 1, 2013. The entire disclosure of theabove application is incorporated by reference as part of the disclosureof this application.

BACKGROUND

This application relates to devices, techniques and systems fordetecting concentrations of injected radionuclides using a handheldnuclear update probe.

In medicine, handheld nuclear-uptake probes, with their audible feedbackand count-rate readouts, are used to locate structures and regions whereinjected radionuclides are present, such as in radio-guided parathyroidand sentinel lymph node surgery with injected Tc-99 sestamibi and Tc-99sulfur colloid radiotracers. Two important parameters for successfulnuclear probe-guided surgery are the probe's high-energy photonsensitivity and its spatial resolution.

These parameters can be modified for a given probe in a number of ways.Increasing or decreasing the energy acceptance window can affect whethermore or fewer scattered photons are counted. Widening the energy windowincreases photon sensitivity but decreases spatial resolution as morescattered high-energy photons are counted. Narrowing the energy windowincreases spatial resolution but decreases photon sensitivity as fewerscattered high-energy photons are counted.

SUMMARY

Devices, techniques and systems are described for facilitatingidentification of a target area during a probe-guided radio-localizationsurgical procedure. The described apparatus, techniques and systems canbe used to implement a nuclear-uptake mode controller integrated into aprobe to allow a user to instantly switch between multiplenuclear-uptake modes. For example, the nuclear-uptake mode controllerintegrated into the probe can be used to instantly switch between ahigh-sensitivity nuclear-uptake mode and a high-resolutionnuclear-uptake mode to effectively identify the target area even in thepresence of interfering nuclear signals by better matching the probe'snuclear detection parameters to a search task for that target area.

In one implementation, an apparatus for performing radio-localization ofnuclear-emitting tissues is described to include a nuclear-uptakesurgical probe with the ability to directly respond to operator inputsto change nuclear uptake parameters from inside the sterile surgicalfield. The apparatus can include one or more of the following features.The apparatus can potentially include a switch located on a hand-pieceof the surgical probe for changing nuclear uptake parameters. Thenuclear uptake parameters can include the photon energy acceptancewindow.

In another implementation, a method for performing a radio-guidedsurgical localization procedure is described to include modifying aphoton energy acceptance window of a nuclear uptake gamma probe systemfrom the sterile field during a surgical procedure.

In another implementation, described is a handheld nuclear-uptakesurgical probe for performing radio-localization of nuclear-emittingtissues, nuclear-uptake surgical probe. The handheld nuclear-uptakesurgical probe as described includes a nuclear-uptake mode controllerconfigured to selectively switch between two or more nuclear-uptakemodes of operation directly from the handheld nuclear-uptake surgicalprobe during the performance of radio-localization of nuclear-emittingtissues, wherein the two or more nuclear-uptake modes of operation havedifferent nuclear-uptake parameters.

The handheld nuclear-uptake surgical probe as described can potentiallyinclude one or more of the following features. The nuclear-uptake modecontroller can be configured to change the nuclear uptake parameters.The nuclear-uptake parameters can include photon energy acceptancewindow. The nuclear-uptake mode controller can be integrated into ahandle of the handheld nuclear-uptake surgical probe. The nuclear-uptakemode controller can include a physical switch located on a handle of thehandheld nuclear-uptake surgical probe to switch between the two or morenuclear-uptake modes of operation. The nuclear-uptake mode controllercan include a touch screen located on a handle of the handheldnuclear-uptake surgical probe to switch between the two or morenuclear-uptake modes of operation. The nuclear-uptake mode controllercan be sealed onto a handle of the handheld nuclear-uptake surgicalprobe to satisfy a sterile environment. The nuclear-uptake modecontroller can be configured to receive an enclosure to seal thenuclear-uptake mode controller onto the handheld nuclear uptake surgicalprobe to satisfy a sterile environment. The handheld nuclear-uptakesurgical probe can include a sensor unit for selectively detecting gammaphotons associated with nuclear-emitting tissues in the two or morenuclear-uptake modes based on changes to the photon energy acceptancewindow. The handheld nuclear-uptake surgical probe can include acommunication medium configured to exchange data with an external probesystem control unit. The communication medium can include a wirelesscommunication medium. The handheld nuclear-uptake surgical probe caninclude a report unit configured to provide feedback to a user, whereinthe feedback includes information associated with the two or morenuclear-uptake modes of operation. The report unit can be integratedinto the handheld nuclear-uptake surgical probe. Algorithms forgenerating the feedback can be different for each selectablenuclear-uptake mode. The feedback information associated with the two ormore nuclear-uptake modes of operation can include identification of acurrently selected one of the two or more nuclear-uptake modes ofoperation. The feedback information can include audible information.

In yet another implementation, a method of operating a handheldnuclear-uptake surgical probe is described. The method can includereceiving, directly at a nuclear-uptake mode controller disposed on thehandheld nuclear-uptake surgical probe, an input initiating a switchfrom one nuclear-uptake mode of operation to another nuclear-uptake modeof operation while the handheld nuclear-uptake surgical probe is inoperation, wherein the two or more nuclear-uptake modes of operationhave different nuclear-uptake parameters Responsive to the inputreceived directly from the nuclear-uptake mode controller disposed onthe handheld nuclear-uptake surgical probe, the handheld nuclear-uptakeprobe can switch to the other nuclear-uptake mode of operation.

The method can potentially include one or more of the followingfeatures. Responsive to the input received directly from thenuclear-uptake mode controller disposed on the handheld nuclear-uptakesurgical probe, the handheld nuclear-uptake probe can modify ahigh-energy photon energy acceptance window of the handheldnuclear-uptake surgical probe associated with the other nuclear-uptakemode of operation. The method can include responsive to the inputreceived directly from the nuclear-uptake mode controller disposed onthe handheld nuclear-uptake surgical probe, outputting feedbackinformation from a reporting unit of the handheld nuclear-uptakesurgical probe, wherein the feedback information includes informationassociated with the nuclear-uptake modes of operation.

In yet another implementation, a method of operating a handheldnuclear-uptake surgical probe during a radio-localization surgicalprocedure is described. The method includes while the handheldnuclear-uptake surgical probe is in operation during theradio-localization surgical procedure, selectively switching between twoor more nuclear-uptake modes of operation directly from the handheldnuclear-uptake surgical probe, wherein the two or more nuclear-uptakemodes of operation have different nuclear-uptake parameters.

The method of operating a handheld nuclear-uptake surgical probe duringa radio-localization surgical procedure can potentially include one ormore of the following features. The method can include selectivelyswitching between two or more nuclear-uptake modes of operationcomprises modifying a high-energy photon energy acceptance window of thehandheld nuclear-uptake surgical probe. The method can includeselectively switching between two or more nuclear-uptake modes ofoperation directly from the handheld nuclear-uptake surgical probe isperformed within a sterile surgical field.

In yet another implementations, described is a handheld nuclear-uptakesurgical probe for performing radio-localization of nuclear-emittingtissues, the handheld nuclear-uptake surgical probe. The handheldnuclear-uptake surgical probe for performing radio-localization ofnuclear-emitting tissues can include a collimator having an opening, thecollimator configured to block gamma photons that are outside ofcollimator's field of view from passing through the collimator. Thehandheld nuclear-uptake surgical probe for performing radio-localizationof nuclear-emitting tissues can include a gamma photon transparentwindow configured to block light from entering the opening of thecollimator. The handheld nuclear-uptake surgical probe for performingradio-localization of nuclear-emitting tissues can include ascintillator configured to produce scintillation photons in proportionto energy of a gamma photon that passes through the collimator andenters the scintillator. The handheld nuclear-uptake surgical probe forperforming radio-localization of nuclear-emitting tissues can include anoptically-coupled photodiode configured to convert the scintillationphotons produced by the scintillator to an induced charge pulseproportional to a number of the scintillation photons produced. Thehandheld nuclear-uptake surgical probe for performing radio-localizationof nuclear-emitting tissues can include a backshield to block gammaphoton signals from entering the optically-coupled photodiode from abackend opposite of the collimator opening. The handheld nuclear-uptakesurgical probe for performing radio-localization of nuclear-emittingtissues can include a signal processing unit configured to process theinduced charge pulse into a voltage pulse with amplitude representingthe energy of the incoming gamma photon for culling into a count ofaccepted voltage pulses. The handheld nuclear-uptake surgical probe forperforming radio-localization of nuclear-emitting tissues can include anuclear-uptake mode controller integrated into the handheldnuclear-uptake surgical probe, the nuclear-uptake mode controllerconfigured to selectively switch between two or more nuclear-uptakemodes of operation having different energy level acceptance windows usedby the signal processing unit to obtain the count of accepted voltagepulses. The handheld nuclear-uptake surgical probe for performingradio-localization of nuclear-emitting tissues can include a wirelesscommunication medium configured to exchange data with an externaldevice.

The handheld nuclear-uptake surgical probe for performingradio-localization of nuclear-emitting tissues can potentially includeone or more of the following features. The nuclear-uptake modecontroller can be integrated into a handle of the handheldnuclear-uptake surgical probe. The nuclear-uptake mode controller caninclude a physical switch located on a handle of the handheldnuclear-uptake surgical probe to switch between the two or morenuclear-uptake modes of operation. The nuclear-uptake mode controllercan be sealed onto a handle of the handheld nuclear-uptake surgicalprobe to satisfy a sterile environment. The nuclear-uptake modecontroller can be configured to receive an enclosure to seal thenuclear-uptake mode controller onto the handheld nuclear uptake surgicalprobe to satisfy a sterile environment.

The above and other aspects, features and implementations are describedin greater detail in the drawings, the description and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of an exemplary nuclear-uptake probesystem.

FIG. 2A shows a cross sectional side view of an exemplary nuclear-uptakeprobe hand-piece.

FIG. 2B shows a three-dimensional perspective view of an exemplarynuclear-uptake probe hand-piece.

FIG. 2C shows a cross sectional side view of an exemplary sensor unit ofa nuclear-uptake probe hand-piece.

FIG. 2D shows a three-dimensional perspective view of an exemplaryoptical light guide and reflector unit of a nuclear-uptake probehand-piece.

FIG. 3 shows a block diagram illustrating an exemplary process ofsensing a nuclear photon, then processing the photon for user feedback.

FIG. 4 shows an energy spectrum of an exemplary nuclear-uptake probe.

FIG. 5 shows a flow diagram of an exemplary nuclear localizationprocedure using a multi-mode handheld probe.

Like reference symbols and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

Devices, techniques and systems described in this document can be usedin various implementations to more quickly and accurately locateconcentrations of radionuclides by allowing a user to quickly and moreclosely match a nuclear-uptake probe's response characteristics to asearch task for locating concentrations of radionuclides. The gammaprobe detection circuitry is designed to allow changing detectioncharacteristics (‘modes’) using a probe-mounted switch. For example,when a user is surveying large areas of an anatomy, the user may preferto start in a high-sensitivity mode that allows for faster probemovement and detection of faint or weak signals associated with theconcentration of radionuclides emanating from deep structures or regionswithin the surveyed areas. Once the locations of the weak signals havebeen roughly identified, the user can switch to a high-resolutionnuclear-uptake mode to slowly and more precisely locate the source ofemissions such as is needed to guide a surgical dissection or todifferentiate a focal signal emanating from a sentinel node near aninterstitial radionuclide injection site.

There are a number of potential benefits to the above describednuclear-uptake mode switching approach. For example, smaller detectors,which can be contained in more compact probes tips, can be used tooptimize or increase interstitial utility. Also, smaller detectorscontain less of the high-energy photon sensing materials used to detectradionuclides, saving on costs. In addition, smaller detectors can beshielded and collimated using less high-Z material (e.g. Tungsten), withfurther cost savings. Implementations of the disclosed technology inthis application can be used to provide a combination of a compact probehand-piece with hand-piece-mounted controls for switching operationalmodes, enabling the surgeon to operate the probe in the sterileenvironment of the surgical field while quickly and easily switchingback and forth between multiple nuclear-uptake modes, in-situ, withoutleaving the sterile surgical field. This combination can expedite andimprove the search task for identifying the locations of theconcentration of radionuclides within the survey areas withoutassistance from others outside the sterile field including the operatingroom staff.

The described devices, techniques and systems can potentially improvenuclear probe-guided localization of radiation-emitting tissues. Ofparticular interest, is increasing the utility of a handheld probeduring surgery by providing user-control of energy window acceptanceparameters, the benefits of which include expediting the localization,the ability to reduce the probe's size and invasiveness, and to minimizethe probe's cost. Moreover, the user (e.g., a surgeon) can operate theprobe to isolate the location of the radiation-emitting tissues fromstart to finish without any interruption or without needing to look awayor move away from the target radiation-emitting tissues.

The energy window of a given nuclear-uptake probe has been normally setto provide the best or ideal compromise between high-energy photonsensitivity and rejection of Compton-scatter. In this way, the user canachieve a balance between the nuclear-uptake probe's performance inquickly surveying for radioactive hotspots or radiation-emitting tissuesand in precisely localizing a radioactive region or structure. A widerenergy window allows more accepted voltage pulses, known as “counts,”converted from detected photons that can be used by the nuclear-uptakeprobe's count-rate processor to produce user feedback with lessstatistical variation, while allowing a shorter count-rate calculationresponse—together providing improved count-rate feedback fidelity. Thisallows the user to move the nuclear-uptake probe faster and to surveywide areas (e.g. multiple nodal basins) in less time or to look forfaint signals (e.g. deep-set sentinel nodes). Narrower energy windowsreject more Compton-scatter, improving the probe's spatial resolutionand allowing the user to more precisely locate focal regions orstructures and to locate radioactive hot spots near the radionuclideinjection site.

The described devices, techniques and systems allow the user to quicklychange the nuclear-uptake parameters of a nuclear-uptake probe from thesterile surgical field without changing the probe. Various technicalfeatures of the device, techniques and systems, and associated examplesare described in this document.

Handheld Multi-Mode Nuclear-Uptake Probe

FIG. 1 shows a perspective view of an exemplary nuclear-uptake probesystem 100, including a processing device, such as an external probesystem control unit 105, for processing the counts data received from anuclear-uptake probe hand-piece 101 (i.e., a handheld probe). Anuclear-uptake mode controller, such as mode switch 102, is located onand integrated into the nuclear-uptake probe hand-piece 101, giving theuser direct access to a mechanism for changing or switching betweenmultiple energy acceptance windows from a sterile surgical field 103.The user can switch between multiple nuclear-uptake modes by simplyinteracting with the mode switch 102 without interruption and withouthaving to move or look away from the tissue area being surveyed. Thus,the user is able to identify the location of the concentration ofradionuclide emitting signals from deep structures or regions within thesurveyed area. A communication medium, such as cable 104, can be used totransmit electronic signals between the handheld probe and the externalprobe system control unit 105. In some implementations, cable 104 couldbe replaced by a wireless connection such as an RF wireless link toprovide more freedom in moving the nuclear-uptake probe hand-piece 101,around during surgery. The external probe system control unit 105, mayinclude an indicator 106, displaying the current energy acceptancewindow mode selection. The indicator 106, can display the selectedenergy acceptance window using various graphical presentations includingphysical indicator lights integrated into the external probe systemcontrol unit 105, virtual indicator lights displayed on a display device(not shown), names of the selected nuclear-uptake modes displayed on adisplay device, or other similar visual indications.

In some implementations, the indicator 106 can include an audioindicator in addition to, or instead of, a visual indicator. Examples ofaudio indicators include various audible sounds that identify theselected nuclear-uptake mode to the surgeon without requiring thesurgeon to look at a display panel or indicator on the external probesystem control unit 105. The various audible sounds can includedifferent tones to represent different modes or the actual names of thedifferent modes. In addition, other similar visual and audio indicatorscan be implemented.

In some implementations, the visual and/or audio indicators can beintegrated into the nuclear-uptake probe hand-piece 101 in order toprovide feedback that identifies the selected nuclear-uptake modewithout distracting or interrupting the user. Thus, the user can obtainfeedback on the selected nuclear-uptake mode without interruption andwithout moving away or looking away from the survey area.

FIG. 2A shows a cross sectional side view of an exemplary nuclear-uptakeprobe hand-piece 101 and FIG. 2B shows a three-dimensional perspectiveview of an exemplary nuclear-uptake probe hand-piece. FIGS. 2A and 2B incombination illustrate various components integrated into the exemplarynuclear-uptake probe hand-piece. As shown, the nuclear-uptake probehand-piece 101 has an integrated mode switch 102, such as push-buttonswitch 202, at least partially protruding through handle 212, forswitching between multiple nuclear-uptake modes. Each of the multiplenuclear-uptake modes has different nuclear-uptake parameters, such asthe energy acceptance window of the handheld nuclear-uptake probe duringoperation. Different energy acceptance windows of the handheldnuclear-uptake probe are described with respect to FIG. 3 below. Thus,switching between different nuclear-uptake modes of operation changesthe energy acceptance window of the handheld nuclear probe duringoperation.

Handle 212 is designed to allow one-handed operation of thenuclear-uptake probe hand-piece 101. For example, the one-handedoperation includes having the integrated mode switch 102, such aspush-button switch 202, positioned on the handle 212, for actuation byat least a finger of a user while holding the nuclear-uptake probehand-piece in one-hand, the same hand whose at least one finger is usedto actuate the integrated mode switch 102.

The nuclear-uptake probe hand-piece 101 includes a gamma photon sensorunit 215, to sense or detect gamma photons. The gamma photon sensor unit215 includes integrated collimator 203 for collimating or directinggamma photons, scintillator 204 for converting the received gammaphotons into optical photons and optically-coupled photodiodc 207 forcollecting and detecting the optical photons from the scintillator 204.Integrated collimator 203 works in conjunction with multi-mode operationof the nuclear-uptake probe hand-piece to block gamma photons that areoutside of its field of view from entering scintillator 204. Thephysical opening of collimator 203 is sealed by a gamma-ray transparentwindow 206, which blocks ambient light from reaching the photodiode 207.This gamma-ray transparent window 206 may be made of a range of suitablematerials including, e.g., a biocompatible and hermetic sealant such assilicone. When a gamma-ray passes through the opening in collimator 203,the gamma-ray enters scintillator 204, producing scintillation photonsin proportion to the gamma ray energy. The techniques described in thisdocument can be used to obtain uniform light collection fromscintillator 204, such as a Cesium Iodide (CsI) scintillating crystal orsimilar materials. Obtaining uniform light collection from scintillator204 can be an enabling factor in obtaining a fine energy resolution,e.g., 10% energy resolution. Scintillation photons are converted by theoptically-coupled photodiode 207 into an induced charge pulseproportional to the number of scintillation photons. Theoptically-coupled photodiode 207 can include low leakage currentphotodiodes, which further enables fine energy resolution.

The nuclear-uptake probe hand-piece 101 also includes a signalprocessing unit such as front-end electronics 208 to process the inducedcharge pulse into a voltage pulse with amplitude representing the energyof the incoming gamma photon for potential culling by energy acceptancewindow processor 216 into a ‘count’, which is processed to provide userfeedback. The energy window acceptance processor can be implementedusing a low cost microprocessor or other similar processing devices andmay perform other functions in the handheld nuclear-uptake probe.Front-end electronics 208 can include processing circuitry, such as alow power, mixed signal application specific integrated circuit (ASIC)to perform enhanced or near optimal charge integration and signalconditioning for scintillator 204 and optically-coupled photodiode 207.An ASIC can be a system-on-chip (SoC) that includes microprocessors,memory blocks including ROM, RAM, EEPROM, flash memory and other largebuilding blocks. In some implementations, front-end electronics 208 caninclude field-programmable gate arrays (FPGA). Programmable logic blocksand programmable interconnects allow the same FPGA to be used in manydifferent applications. The front-end electronics as described canenable automatic compensation for variations in manufacturing andenvironmental conditions, to achieve at least a 90-electron noise budgetat room temperature, for example.

The energy acceptance window processor 216 may be located in the probehand-piece 101 or the external probe system control unit 105. Printedcircuit assembly 210 contains mode switch contacts 211 that sense userinput in response to the user interfacing with the nuclear-uptake modeswitch 102 to change or switch between multiple nuclear-uptake modes andthus switch between multiple energy-window acceptance modes (i.e.,nuclear-uptake modes) by depressing switch actuator 202. The necessaryelectronics for the nuclear-uptake mode switch 102 are contained incannula 209, which can also provide EMI shielding for the sensitivefront-end low-noise sensing components.

Nuclear-uptake probe hand-piece 101 can also include additional controlunits such as control and report unit 217 that allows the user to accessand control various probe functions on the nuclear-uptake probehand-piece 101. The additional control units such as control and reportunit assembly 217 can be implemented using multiple user interfaceelements (e.g., buttons, toggle switches, dials, etc.), and the numberof user interface elements employed can be at least partially dependenton the number of control functions implemented into a design. In theexample shown in FIG. 2B, the additional control units such as controland report unit assembly 217 is shown with three additional userinterface elements. Count rate controller 217 a can be implemented as abutton associated with obtaining the count rate during the search mode.Pressing and holding the count rate controller button 217 a can initiatethe extended count rate function to determine whether a statisticallysignificant count rate can be obtained, and if it can be obtained, itscount rate value. To alert the user of the extended count rate operatingduring a scan mode, an audible alert message can be broadcasted torequest that the user hold steady the handheld nuclear-uptake probehand-piece 101. An example of the broadcast message may be: “Extendedcount, please hold the probe steady.” Once a hotspot of theconcentration of injected radionuclides has been identified, thehandheld nuclear-uptake probe hand-piece 101 can be switched betweenmultiple modes (e.g., search and scan modes) while identifying othertissue areas that may be within some predetermined range (e.g., 10%) incomparison to the signal detected from the hotspot to identify whichtissues should be excised.

In the example shown in FIG. 2B, control and report unit 217 can alsoinclude a range controller 217 b implemented as a toggle switch. Therange controller 217 b can be used to control the volume of any audiblefeedback based on the signal from the handheld nuclear-uptake probehand-piece 101, for example from external probe system control unit 205.The range controller 217 b can also be used to vary the audio feedbacksignal range in comparison to the input count range. In someimplementations, the nuclear-uptake mode controller 102 and associatedbutton 202 can be integrated with the other user interface elements suchas control and report unit 217.

Control and report unit 217 also provides voice or audioreporting/feedback during surgery to enable the user (e.g., a surgeon)to maintain her visual focus on the target incision site. Thereporting/feedback includes information associated with the multiplenuclear-uptake modes. For example, the reporting/feedback informationcan include information to identify the currently selectednuclear-uptake mode. Also, the reporting/feedback information caninclude listing of choices of the multiple nuclear-uptake modesavailable for the user to select. In addition, the reporting/feedbackinformation can be processed using algorithms that arc different foreach mode selected. For example, audio feedback may be filtereddifferently in high-sensitivity mode than it is in high-resolution modeto improve its stability or response time. Reporting/feedback during theoperation of the nuclear-uptake probe hand-piece 101 can be implementedusing techniques other than voice or audio. For example, various tactilefeedback techniques such as haptic feedback can be used. Otheralternatives include visual feedback such as by varying the intensity,brightness, color and/or on/off frequency of one or more lights as thenuclear-uptake probe hand-piece is moved closer or away from thelocation of the concentration of injected radionuclides.

As described with respect to FIGS. 1, 2A and 2B above, the wiredcommunication medium 104 can be implemented by providing a connector 213for physically connecting data communication wire 214 to printed circuitassembly 210. Alternatively, the handheld nuclear-uptake probehand-piece 101 can communicate with an external device using one or morewireless communication links 104 a. For example, Bluetooth Low Energy(BLE) circuitry 218 can be used to enable low cost, battery drivenwireless link to external probe system control unit 105 or othercomputing devices 107 for exchanging data and/or commands with thenuclear-uptake probe hand-piece. Other examples of wireless connectivityinclude 802.11 family of WiFi technologies. Examples of the computingdevices 107 capable of wirelessly communicating with the nuclear-uptakeprobe hand-piece include portable computing devices, such as a tabletcomputer 107 a, a laptop 107 b, a smart phone 107 c, iPad, and wearabledevices include a smart watch.

Mode switch 102, such as push button switch 202 and associated modeswitch contacts 211 are integrated into the nuclear-uptake probehand-piece 101 in a manner appropriate for the sterile environment of asurgical field. Various techniques can be implemented to maintain asterile environment. For example, mode switch 102, such as push buttonswitch 202 and associated mode switch contacts 211 can be sealed intothe nuclear-uptake probe hand-piece 101 to satisfy sterile environment.In some implementations, a hermetic seal can be used. Alternatively,mode switch 102, such as push button switch 202 and associated modeswitch contacts 211 can be designed or packaged to receive or interfacewith a separate device that prevents biological materials, chemicals,fluids and other surgical materials from entering the nuclear-uptakeprobe hand-piece during surgery. For example, mode switch 102, such aspush button switch 202 and associated mode switch contacts 211 can bedesigned or packaged to receive or interface with a cap, cover, housing,a surgical drape, and other like materials and devices that provides aseal to satisfy sterile environment. In addition, the nuclear-uptakeprobe hand-piece 101 can be manufactured as a sterile disposable device.

FIG. 2C shows a cross sectional side view of an exemplary sensor unit ofa nuclear-uptake probe hand-piece. FIG. 2D shows a three-dimensionalperspective view of an exemplary optical light guide and reflector unitof a nuclear-uptake probe hand-piece. FIGS. 2C and 2D in combinationshow optically related components that provide for a highly efficientsensor unit 215 to detect gamma photons emitted from the concentrationof injected radionuclides. Sensor unit 215 can include opticalcomponents that enable a highly efficient photon detection/sensor.Integrated collimator 203, selectively blocks gamma photons that areoutside of its field of view from entering scintillator 204. It includeslow-Z and low density optical blocking plug 219 at the front end toprevent ambient light from entering scintillator 204. Optical reflectorand light guide 220 are placed next to the scintillator 204, allowingfor uniform light collection from the scintillator 204 (e.g., a CsIscintillating crystal).

Optical light guide and reflector 220 is shown in further detail in FIG.2D. In an exemplary design, optical light guide and reflector 220 canroute around wire bonds for ease of manufacture. Optical light guide andreflector 220 provides substantially optimal light collection even forthe thicker bond line required by the need for wire bonding due to frontside illumination because optical light guide and reflector 220 is anoptical diffuse reflector with high reflectivity. Without this design,light collection would be suboptimal. Optical light guide and reflector220 can be pre-molded out of optically reflective material, which makesthe assembly process easy and fast (versus potting with reflectiveepoxy), and also has better optical performance. Self fixturing, whichkeys off of the outline of the photodiode, eases assembly. Also,additional cutouts can be used to simplify assembly. In the exampleshown in FIG. 2D, there are 4 cutouts even though there are only twowire bonds so the operator does not need to have it aligned to thecorrect polarity. Optical light guide and reflector 220 can be designedto have a snap-lock (similar to a Lcgo (R) block, for example) interfaceto the upper reflector, holding the crystal which makes it easy tohandle and attach with an optical medium (epoxy/silicone/grease, etc.).

The sensor unit 215 includes backshield 221 disposed after the front-endelectronics to block or shield the sensing unit 221 against gamma photonsignals entering from a backend (e.g., opposite end of the probe tip)towards the tip of the nuclear-uptake probe hand-piece 101. In anexemplary design, the backshield 221 includes two half cylinders ofbackshield material, a sandwich board and a plug that goes through thecenter so to provide back gamma shielding. Also, backshield 221 acts aselectrical grounding. Backshield 221 can be formed using an injectionmolded tungsten part to achieve low cost. In addition to providing backgamma photon shielding, backshield 221 provides electromagneticinterference (EMI) shielding for radio frequency (RF) signals from thewireless circuitry 218. For ease of manufacture, the backshield 221 canbe formed to have interlocking tabs and a symmetric design.

The design of the described sensor unit 215, including the individualcomponents provides for substantially optimal light collection and thusefficient and optimal gamma photon detection with fine resolution.Because of the efficiency and fine resolution of the sensor unit 215,the ability to switch between different nuclear-uptake (or energyacceptance window) modes from the nuclear-uptake probe hand-piece 101,without leaving the sterile surgical field becomes advantageous.Furthermore, the detector material type and design provide for improvedpeak to total counts (e.g. there is no hole tailing such as is the casewith CZT/CdT based detectors) which would prohibit the practicalimplementation of such mode switching due to the reduction in efficiencyresulting from a narrow energy window.

While FIGS. 2A, 2B, 2C and 2D show an example implementation of a singlepush button 102, with associated switch actuator 202, and mode switchcontacts 211, more than one push button 102, can be used. For example, aseparate dedicated push button can be used to represent eachnuclear-uptake mode. In the multi-push button example, multiple switchactuators 202, and switch contacts 211, may be needed.

The nuclear-uptake mode switch 102, and the associated switch contacts211, are not limited to a push-button. Other physical and virtual switchmechanisms that perform substantially the same functions can beimplemented. Examples of physical switch mechanism include rotary dials,multidirectional toggle switches, slide switches, and other similarphysical switches. Examples of virtual switch mechanisms include touchsensitive areas on a touchscreen or touchpad that sense physical touchor capacitive charge differences in response to a user touching orhovering near the touch sensitive areas corresponding to differentnuclear-uptake modes. In some implementations, touch-free inputmechanisms can replace the physical and virtual switches. Examples oftouch-free input mechanisms include voice activation and gesture ormotion detection and tracking.

Nuclear Photon Detection and Signal Processing Using Multi-ModeSwitching

FIG. 3 shows a block diagram illustrating an exemplary process 300 ofsensing/detecting a nuclear photon, then processing the sensed/detectedphoton for user feedback. Sensing/detection process 301 occurs in asensor, such as the gamma photon sensor unit 215, to capture alldetectable events regardless of their energy. Signalprocessing/front-end electronics process 302, is performed in front-endcircuitry/electronics, such as front-end electronics 208, to convertanalog output signal from sensing process 301, into a voltage pulse,with the magnitude proportional to the energy of the incoming gammaphoton. In energy spectrum analyzer process 303, the voltage pulses fromthe signal processing/front-end electronics process 302, are accepted orrejected based on the application of the selected energy acceptancewindow. This process can be changed/switched by depressing thepush-button switch actuator 202. In user feedback process 304, acceptedvoltage pulses (i.e., counts) are processed and timed for count-rateanalysis and user feedback.

FIG. 4 shows an energy spectrum of an exemplary nuclear-uptake probe.Specifically, shown in FIG. 4 is a typical spectrum plot of energylevels of gamma photons accumulated by the nuclear-uptake probe 101,over a fixed time period with corresponding probe output voltage levelsfor the radioisotope Tc-99. The 141 KeV full-energy gamma ray peak 401,the Cesium Iodide (CsI) escape peak 404, and the X-ray fluorescence peak405 (Kalpha and Kbeta emission from the inside of the collimator 203stimulated by incident gamma-rays), are shown. Detected events with anenergy level below the X-ray energy peak 405 are caused by electronicnoise and low level background. They are removed by a hardware-based lowlevel discriminator which selects only events with energy above thisthreshold. Cutoff lines 403, 408, and 409 demonstrate three potentialand different lower energy cutoffs, and cutoff line 402 represent thehigher energy cutoff or upper level discriminator. The first, at cutoffline 409, depicts a threshold that would produce a relatively highcount-rate but that would include more scattered gamma photons includingoff-angle photons that enter the collimator 203, but fail to reach thescintillator 204; the second, at cutoff line 408, that would providehigher scatter rejection of off-angle photons but with a lower countrate; and the third, at cutoff line 403 that would provide even higherscatter rejection than at cutoff line 408, but with an even lowercount-rate. Depressing nuclear-uptake mode switch 102 can switch betweencutoff lines 403, 408 and 409 to produce higher-resolution or highercount rates. In the example shown in FIG. 4, the highest-sensitivitywindow is illustrated to cover the energy level range from cutoff line409 to cutoff line 402. The higher-sensitivity window is illustrated tocover the energy level range from cutoff line 408 to cutoff line 402.The high-resolution window is illustrated to cover the energy levelrange from cutoff line 403 to cutoff line 402.

Example Nuclear Localization Procedure Using Multi-Mode Handheld Probe

FIG. 5 shows a flow diagram of an exemplary nuclear localizationprocedure performed using a multi-mode handheld probe. First, in step501, the patient is injected interstitially with a dose of tracer (e.g.Tc-99 Sulfur Colloid as for locating sentinel nodes), or systemicallywith a dose of radioisotope-containing pharmaceutical (e.g. Tc-99Sestamibi as for locating parathyroid adenomas). An appropriate time isallocated for allowing the dose to concentrate according to itsbiological interaction. In step 502, the multi-mode nuclear-uptakehandheld probe as described in this document is deployed inhigh-sensitivity mode to survey for the location of concentratedradioisotope emissions. The use of high-sensitivity mode allows the userto move the probe more quickly thanks to the relative abundance ofhigh-energy photon counts that are available for audio-feedback. When alocation of concentrated radioisotope emissions is identified, themulti-mode nuclear-uptake handheld probe can be switched as in step 503,to operate in high-resolution mode to more precisely locate the sourceof emissions and to better differentiate focal sources from backgroundemissions. Once the location of the source has been preciselyidentified, the multi-mode nuclear-uptake handheld probe still inhigh-resolution mode can be used as in step 504, to guide the dissectionof the anatomical structure or region. The small probe tip enabled bythe devices, techniques and systems described in this document canpotentially minimize surgical access requirements while improvingvisualization of the dissection. Moreover, the small probe tip providesfine spatial resolution for discriminating between closely-spacedanatomical structures.

Accordingly, it is to be understood that the embodiments andimplementations of the devices, techniques and systems described hereinare merely illustrative of various potential applications. Potentialvariations to the devices, techniques and systems described in thisdocument can include, for example, 1) the use of other methods thatcould be made available to the user to change the uptake parameters fromthe sterile surgical field such as voice commands, gestures, orfoot-pedals; 2) methods other than changing the energy acceptance thatwould result in a change to the sensitivity and/or the resolution suchas electrically switching between different on-board sensorconfigurations; and 3) the use of other high-energy photon sensors suchas bulk semiconductors (e.g. CZT or CT) or crystal scintillators coupledto photomultiplier tubes.

While this document contains many specifics, these should not beconstrued as limitations on the scope of any invention or of what may beclaimed, but rather as descriptions of features that may be specific toparticular embodiments of particular inventions. Certain features thatare described in this specification in the context of separateembodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments.

Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on whatis described and illustrated in this document.

1-24. (canceled)
 25. A method of monitoring a nuclear-uptake surgicalsystem, the method comprising: receiving from a handheld probe of thenuclear-uptake surgical system, at a probe system control unit, aselection of a photon energy acceptance window of the handheld probe,wherein a nuclear-uptake mode controller disposed in the handheld probeis communicatively coupled to the probe system control unit; anddisplaying, on the probe system control unit, the selected energyacceptance window of the handheld probe.
 26. The method of claim 1,wherein the handheld probe is communicatively coupled to the probesystem control unit via a cable.
 27. The method of claim 1, wherein thehandheld probe is communicatively coupled to the probe system controlunit via a wireless link.
 28. The method of claim 3, wherein thewireless link comprises a Bluetooth Low Energy circuit.
 29. The methodof claim 1, wherein displaying the selected energy acceptance windowfurther comprises emitting at least one of a visual indicator and anaudio indicator.
 30. The method of claim 1, wherein the probe systemcontrol unit comprises at least one of a computer, a laptop, a smartphone, and a wearable device.
 31. A handheld nuclear-uptake surgicalprobe comprising: a handle; and a sensor unit connected to the handleand configured to detect gamma photons external to the handle, thesensor unit comprising: a collimator; a scintillator disposed within thecollimator; and an optical light guide comprising a reflector anddisposed adjacent the scintillator.
 32. The handheld nuclear-uptakesurgical probe of claim 7, wherein the sensor unit further comprises anoptical blocking plug disposed within the collimator and adjacent thescintillator, wherein the optical blocking plug is configured to preventambient light from entering the scintillator.
 33. The handheldnuclear-uptake surgical probe of claim 7, wherein the sensor unitfurther comprises a backshield disposed proximate the handle.
 34. Thehandheld nuclear-uptake surgical probe of claim 9, wherein thebackshield comprises a gamma photon shield and an electromagneticinterference shield.
 35. The handheld nuclear-uptake surgical probe ofclaim 9, wherein the backshield comprises a pair of injection moldedtungsten parts.
 36. The handheld nuclear-uptake surgical probe of claim7, wherein the optical light guide further comprises a plurality ofcutouts.
 37. The handheld nuclear-uptake surgical probe of claim 7,wherein the optical light guide further comprises a plurality of wirebonds.
 38. The handheld nuclear-uptake surgical probe of claim 7,further comprising a nuclear-uptake mode controller disposed in thehandle and configured to selectively set a photon energy acceptancewindow of the handheld surgical probe.
 39. A handheld nuclear-uptakesurgical probe comprising: a handle; a nuclear-uptake mode controllerconfigured to selectively set a photon energy acceptance window of thehandheld surgical probe, wherein a first setting of the photon energyacceptance window corresponds to a scan mode and a second setting of thephoton energy acceptance window corresponds to a search mode; and acount rate controller configured to obtain a count rate during each ofthe scan mode and the search mode.
 40. The handheld nuclear-uptakesurgical probe of claim 15, wherein the count rate controller isconfigured to detect an extended count rate during the scan mode. 41.The handheld nuclear-uptake surgical probe of claim 16, furthercomprising an audible indicator communicatively coupled to the countrate controller.
 42. The handheld nuclear-uptake surgical probe of claim17, wherein the audible indicator is configured to broadcast a messageupon the detection of the extended count rate during the scan mode. 43.The handheld nuclear-uptake surgical probe of claim 15, wherein thecount rate controller comprises a button disposed on the handle.
 44. Thehandheld nuclear-uptake surgical probe of claim 15, further comprising aswitch disposed on the handle and communicatively coupled to thenuclear-uptake mode controller to selectively initiate the setting ofthe photon energy acceptance window.